The World Health Organization (WHO) says it is unable to concretely identify the origins of the virus that led to the Covid-19 pandemic, in part due to a lack of cooperation from China.

In a report published on 27 June, WHO reiterated its stance on how the SARS-Cov-2 virus originated, claiming the “best supported hypothesis” is a zoonotic source that transferred to humans.

The commonly accepted origin of SARS-Cov-2 is from animals being sold at a market in Wuhan, China. The WHO’s Scientific Advisory Group for the Origins of Novel Pathogens (SAGO) – a panel comprising 27 independent, international, multidisciplinary experts – has been investigating a range of possibilities since the pandemic.

Several hypotheses are on the table, one of which is that the virus was deliberately manufactured in a lab and then leaked in a biosafety breach.

While pointing to a zoonotic source as the most likely source based on analysis of interviews, research papers, government reports, among others, the report could not rule out other hypotheses, including a lab leak, because requests for information had not been heeded.

The WHO has requested that China share hundreds of genetic sequences from individuals with Covid-19 early in the pandemic. In addition, the Chinese Government was asked to send over more detailed information about the animals sold at markets in Wuhan, along with details on biosafety conditions at laboratories in the city. The country has so far not shared this information either with SAGO or WHO.

Future pandemic protection

Apart from the scientific endeavour of the project, the report also aims to use knowledge of SARS-CoV-2 to help fight future pandemics. Understanding the origins of the virus and how it sparked a pandemic can help safeguard public health frameworks.

WHO director general Dr Tedros Adhanom Ghebreyesus said: “As things stand, all hypotheses must remain on the table, including zoonotic spillover and lab leak. We continue to appeal to China and any other country that has information about the origins of Covid-19 to share that information openly, in the interests of protecting the world from future pandemics.”

Dr Marietjie Venter, who is chair of SAGO, commented: “Understanding the origins of SARS-CoV-2 and how it sparked a pandemic is needed to help prevent future pandemics, save lives and livelihoods, and reduce global suffering.”

Information on Covid-19 is critical for preparing public health countermeasures against the next unknown pathogen threatening a pandemic, commonly called ‘Disease X’. This includes understanding how different modalities of vaccines work, which has knock-on effects for supply chain logistics and manufacturing coordination.